Knowledge

2 linked papers

3 linked papers

Nature of charge density waves and metal-insulator transition in pressurized La₃Ni₂O₇

This study employs neutron scattering techniques to elucidate the spin order and dynamics in bilayer nickelate La₃Ni₂O₇ single crystals. In the ambient-pressure parent phase, clear spin excitations are observed at the reciprocal-space position Q = (0, 0.5, 2.5), exhibiting a spin gap of approximately 5 meV and pronounced in-plane anisotropic dispersion—band-edge softening along the transverse direction reveals competing exchange interactions. The excitations display an out-of-plane modulation with bilayer periodicity, directly confirming antiferromagnetic interlayer coupling. Based on linear spin-wave theory, the experimental dispersion can be accurately described by a bilayer Heisenberg Hamiltonian incorporating strong interlayer exchange and competing in-plane couplings, with a stripe-type magnetic order. After normalizing the spectral intensity to absolute units, it is found that although the spin-wave bandwidth is only 25% of that in cuprates, the local dynamical magnetic susceptibility is significantly enhanced at comparable energies, and the total fluctuating magnetic moment is comparable to that of cuprates. These results reveal that intermediate-energy spin excitations originating from strong electronic correlations are an intrinsic feature of this system, establishing a magnetic framework fundamentally distinct from that of cuprates and providing direct evidence for understanding the pairing mechanism of superconductivity in this system.

2 linked papers

6 linked papers

1 linked paper

2 linked papers

1 linked paper

2 linked papers